Isolating Benzenium Ion Salts Full article
| Journal |
Journal of the American Chemical Society
ISSN: 0002-7863 , E-ISSN: 1520-5126 |
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| Output data | Year: 2003, Volume: 125, Number: 7, Pages: 1796-1804 Pages count : 9 DOI: 10.1021/ja027336o | ||||||
| Tags | Alkalinity; Benzene; Negative ions; Nuclear magnetic resonance; Probability density function; X ray diffraction analysis | ||||||
| Authors |
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| Affiliations |
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Funding (3)
| 1 | National Institutes of Health | GM 23851 |
| 2 | National Science Foundation | CHE-0095206 |
| 3 | Civilian Research and Development Foundation | RC1-2399-NO-02 |
Abstract:
When partnered with carborane anions, arenium ions are remarkably stable. Previously investigated only at subambient temperatures in highly superacidic media, protonated benzene is readily isolated as a crystalline salt, thermally stable to >150 °C. Salts of the type [H(arene)][carborane] have been prepared by protonating benzene, toluene, m-xylene, mesitylene, and hexamethylbenzene with the carborane superacid H(CB11HR5X6) (R = H, Me; X = Cl, Br). They have been characterized by elemental analysis, X-ray crystallography, NMR and IR methods. Solid-state 13C NMR spectra are similar to those observed earlier in solution, indicating that lattice interactions are comparable to solution solvation effects. The acidic proton(s) of the arenium cations interact weakly with the halide substituents of the anion via ion pairing. This is reflected in the dependence of the C−H stretching frequency on the basicity of the carborane anion. Bond lengths in the arenium ions are consistent with predominant cyclohexadienyl cation character, but charge distribution within the cation is less well represented by this resonance form. Structural and vibrational comparison to theory is made for the benzenium ion (C6H7+) with density functional theory at B3LYP/6-31G* and B3P86/6-311+G(d,p) levels. The stability of these salts elevates arenium ions from the status of transients (Wheland intermediates) to reagents. They have been used to bracket the solution-phase basicity of C60 between that of mesitylene and xylene.
Cite:
Reed C.A.
, Kim K-C.
, Stoyanov E.S.
, Stasko D.
, Tham F.S.
, Mueller L.J.
, Boyd P.D.W.
Isolating Benzenium Ion Salts
Journal of the American Chemical Society. 2003.
V.125. N7. P.1796-1804. DOI: 10.1021/ja027336o
WOS
Scopus
РИНЦ
ANCAN
OpenAlex
Isolating Benzenium Ion Salts
Journal of the American Chemical Society. 2003.
V.125. N7. P.1796-1804. DOI: 10.1021/ja027336o
WOS
Scopus
РИНЦ
ANCAN
OpenAlex
Files:
Full text from publisher
Dates:
| Submitted: | Jun 17, 2002 |
| Published print: | Feb 19, 2003 |
Identifiers:
| Web of science: | WOS:000181088000029 |
| Scopus: | 2-s2.0-0037442636 |
| Elibrary: | 13426853 |
| Chemical Abstracts: | 2003:49659 |
| Chemical Abstracts (print): | 138:237760 |
| OpenAlex: | W1977513866 |